Buchi Rotavapor R-187EL User manual

1
BÜCHI Rotavapor R-187EL
en, Version B (42 pages) Order-No.
R-187 Instructions 96611
Contents
Contents
1 Scope of delivery 2
2 Safety 3
3 Function 7
3.1 Functional principle 7
3.2 Overview of components 8
4 Putting into operation 9
5 Operating the Rotavapor 17
6 Maintenance 21
7 Taking out of operation 24
8 Spare parts 25
8.1 Glass assembly 27
8.2 Hydraulic drive 29
8.3 Cooling water and vacuum tube connections 31
8.4 Gear head 33
8.5 Thermostat valve 36
8.6 Bath electrical unit 37
8.7 Accessories 38
9 Appendix 40
Subject to change without prior announcement. No part of these
operating instructions may be reproduced in any form or be pro-
cessed, duplicated or distributed by electronic or optical means
without the written permission of Büchi Labortechnik AG.
All rights reserved.
Copyright © Büchi Labortechnik AG 1996
Read these operating instructions carefully before you use the
Büchi Rotavapor R-187. Keep these instructions in a safe
place close to the unit for quick reference whenever required.
Chapter 2 contains important notes concerning safety. It is impe-
rative to read these notes in order to operate the rotary evaporator
safely.

2
BÜCHI Rotavapor R-187EL
Material
1 Chassis complete with control and drive unit,
heating bath
1 50L or 100L evaporating flask
2 20L receiving flask
1 Glass assembly:
descending
reflux
(See page 12 and 13 for illustrations)
Enclosed items: Order-No.
1 Hex head wrench set SW2-SW10 03776
1 Hook wrench small 03753
1 Hook wrench large 34870
1 Seal removal tool 20057
1 Hydraulic oil 15L 28830
1 Operating instructions
German 96610
English 96611
French 96612
Table 1: Scope of delivery
1 Scope of delivery
1 Scope of delivery
Figure 2: R-187,descending glass
assembly
Figure 1: R-187, Reflux glass
assembly

3
BÜCHI Rotavapor R-187EL 2 Safety
2 Safety
This appliance is built in accordance with the state of engineering
and the recognized rules of safety.
Nevertheless, it can still be a source of risks and hazards:
•if used by persons with insufficient training
•if used for purposes other than that for which it is intended.
2.1 Symbols
Information about hazards which can lead to serious material
damage or cause serious or potentially fatal injury.
Warning Information about hazards which can be harmful to
your health or lead to material damage.
Please note
Information about technical requirements. Non-observance can
lead to malfunctions, inefficiency and lost production.
2.2 Requirements to be met by the customer
The Rotavapor must only be operated by persons who have
the training or professional experience to comprehend the
hazards that can arise when using the instrument.
Personnel without such training or persons currently undergoing
a course of training require thorough instruction. These operating
instructions should form the basis of this instruction.
2.3 Proper use
The Rotavapor is designed and built for use in kilo or scale-up
labs and production departments. It is intended to be used on
jobs involving the evaporation and condension of solvents.
The Rotavapor is used for:
•concentrating solutions and suspensions
•drying powders and granules
•recrystallization
•reflux reactions
•synthesis and purification of fine chemicals
•recycling and concentration of solvents
For the Rotavapor to be used properly, it must also be cleaned
and handled carefully as descibed in these operating instructions.

4
BÜCHI Rotavapor R-187EL2 Safety
2.4 Improper use
Any use other than those already listed, and any application
that does not conform with the technical data is deemed to
be a case of mis-use. The customer shall bear sole
responsibility for any damage caused by such mis-use.
The following applications in particular are prohibited:
•Production and processing of substances which may lead
to spontaneous reactions, e.g. explosives
•Rotating the filled evaporation flask which is not immersed
in the water bath (risk of breakage)
•Drying of hard or brittle materials (e.g. stones, soil samples)
which can cause destruction of the evaporating flask
•Shock cooling of the evaporating flask
The Rotavapor is not designed to be operated with positive
pressure
2.5 General hazards
General hazards arise from:
•the hot water or oil bath (risk of scalding).
•polluted solvents which in the course of distillation may
form residues that lead to spontaneous reactions (e.g.
metal hydrides)
•solvents which can form peroxides (risk of explosion).
•solvents with low ignition, flash and/or explosion
temperatures.
•mixtures of unknown composition or with impurities.
•damaged glassware.
•combustible gases or solvent vapors which are not
permitted by the explosion proof safety standards.
•electrostatic charges during operation, e.g. when
decanting combustible solvents and when drying powders.
•coolant temperatures lower than the distillate´s freezing
point (will diminish the capability of the condenser coils to
cool the vapor, thus causing a build up of solvent vapor
and dangerous positive pressure).
2.6 Safety measures
Regional and local laws and regulations must be observed.
The unit is grounded internally in order to divert electrostatic
charges from the Rotavapor. There are also ways to divert
electrostatic charges from the glass couplings, by connecting
the couplings together with wires, which are also grounded.

5
BÜCHI Rotavapor R-187EL 2 Saftey
It is imperative to wear personal safety items such as goggles,
protective clothing and gloves.
Be sure to use the supplied hook wrench to tighten the
evaporating flask with normal firmness so that the flask does
not become loose on its own.
Do not start distillation until the evaporating flask is immersed
in the bath as there is a risk of the flask neck breaking off
under the heavy weight.
There is risk of scalding when replacing hot evaporating flasks.
This can be prevented by wearing suitable gloves.
Examine the glass components regularly for signs of damage,
including chips or cracks.
Never interrupt the ground conductor (protective ground) or
you may suffer an electric shock.
It is the customer´s duty to instruct his personnel. These
operating instructions are also available in other languages
for this purpose. They are to be considered an integral part of
the Rotavapor and must always be kept at the unit´s point of
use.
The customer shall notify the manufacturer immediately of
any incidents involving safety aspects during the use of the
appliance.
Modifications
Modifications are only permitted after consulting with the
manufacturer and obtaining his written consent.
It is imperative to use only the glass assembly recommended
by the manufacturer. Never assemble odd glass components
at random.
You are allowed to install and remove only those specific
parts of the Rotavapor that are so designed to enable it to
perform its function. You can do so either by hand or with
the tool supplied with the instrument. Apart from authorized
maintenance personnel, no one is allowed to remove any
safety devices and covers with a standard tool. Touching live
parts may result in fatal injury!

6
BÜCHI Rotavapor R-187EL
2.7 Safety elements
Chassis:
•Electrostatic conducting chassis wheels are lockable for
stationary positioning.
Drive unit:
•Lock pin on the drive unit to safely attach the evaporating
flask.
•Safety pressure valve opens if the drive head overloads or
becomes blocked.
Heating bath:
•Automatic lowering of bath in case of a power failure to
protect the flask contents from overheating.
•Level regulation with bath overflow.
Glassware:
•Use of high-grade, inert 3.3 borosilicate glass.
•Grease-free ground glass joints with inserted PTFE seal
for inert, non-stick vacuum connections
•Flexible ball-and-socket couplings with plastic insert for
stress-free fastening of the ground glass joints.
•Threaded glass connections on all remaining glass joints
to prevent glass breakage.
Optional:
•PLASTIC+GLAS protective coating for glass components
improves their mechanical resistance to breakage and
increases protection against glass splinters.
2 Saftey

7
BÜCHI Rotavapor R-187EL
3 Function
A vacuum rotary evaporator is used to carry out single-stage
distillations at high speed and low stress. The process is
based on the evaporation and condensation of solvents using
a rotating evaporating flask.
The operation is made under vacuum to protect the product
from stress and improve efficiency.
The vacuum seal of the rotation unit is tight in the low pressure
range. If any harmful solvents are evaporated, a minimal low
pressure is needed to guarantee a secure closeness
3.1 Functional principle
The vacuum rotary evaporator is used to carry out single-
stage distillations at high speed and low stress. The process
is based on the evaporation and condensation of solvents
using a rotating evaporating flask. The distillation can be
performed under vacuum or at atmospheric pressure.
Evaporation zone
The solvent in the evaporating flask is heated by the hot
bath. The rotating evaporating flask generates intensive
turbulence in the flask and forms a thin film of solvent on
the inside surface of the flask. This combination of
turbulence and film prevents local overheating and guaran-
tees a high rate of distillation.
Rotary drive
The drive unit ensures uniform rotation of the evaporating
flask.
Cooling zone
The solvent vapor flows at high speed into the condenser.
This is where the solvent vapor´s energy is transferred to
the cooling medium (e.g. water) - the solvent condenses.
Receiving flask
The receiving flask is used to collect the condensate.
Vacuum connection
The solvent´s boiling point temperature can be lowered by
reducing the system pressure. This results in lower ther-
mal loading and less stress on the product.
The efficiency of the evaporator is influenced by the pressure
of distillation (vacuum), the temperature of the heating bath,
the speed of rotation and the size of the evaporating flask.
For details of how to select the optimum distillation conditions,
see Chapter 5.3, Selecting the conditions of distillation.
Figure 3: Functional principle of the R-187





3 Function

8
BÜCHI Rotavapor R-187EL
3.2 Overview of components
Evaporating flask
Control panel
Chassis with hydraulic drive
Bath
Glass assembly
Sealing system
Receiving flask
Figure 4: Components of the R-187







3 Function

9
BÜCHI Rotavapor R-187EL
4 Putting into operation
The danger zone around the Rotavapor R-187 has a radius
of 10 m. Be careful if you have to do (repair) works in this
area, because of the risk of damaging glass components.
Damaged glass components can cause implosions, when
they are used under vacuum.
4.1 Place of installation
The dimensions of the rotary evaporator are with the
reflux glass assembly: L = 163 cm
W = 76 cm (50L)
W = 90 cm (100L)
H = 280 cm
with the descending L = 163 cm
glass assembly: W = 76 cm (50L)
W = 90 cm (100L)
H = 265 cm
Net weight: approx. 340 kg
Ambient temperature: 5 °C –40 °C
Point of use: A firm level surface, in a rarely frequented area
to minimize glass breakage.
Always make sure that the unit´s explosion-proof classification
complies with the room´s explosion-proof classification.
4.2 Unpacking
Open all boxes carefully to avoid any glass breakage.
Wooden crate
Box for the distribution piece
Box for the oil canister
Box for the other glass components
Box for the metal parts
Box for the small condenser
Box for the large condenser
Box for the evaporating flask
Support bar
Box for the receiving flask (top view)
Open carefully the wooden crate on the side wall marked
„open this side“, remove all boxes carefully from crate.
Then lift the Rotavapor out of the crate with a fork-lift truck.
After positioning the unit at its point of use, lock the wheels.
4 Putting into operation
Figure 5: R-187 packaging










10
BÜCHI Rotavapor R-187EL
4.3 Hydraulic oil
Starting up the Rotavapor without oil can cause damage to
the drive unit.
Oil filter
Oil filling port
Level indicator
•1. Open front panel
•2. Pour in approx. 10 litres of hydraulic oil, observing the
‘Max.’mark on the level indicator.
Figure 6: Hydraulic unit with oil filling neck



4.4 Mounting the support (for reflux glass
assembly)
•Push support bar on the cone and screw tight with
clamp 
•Tighten the condenser contact ring a distance of 770
mm above the top edge of the housing.
•Tighten the aftercondenser clamp a distance of 325
mm above the top edge of the housing.
Figure 7: Support for reflux glass assembly




4 Putting into operation


11
BÜCHI Rotavapor R-187EL
4.5 Mounting the support
(for descending glass assembly)
•Push support bar  on the cone and screw tight with
clamp 
•Tighten the condenser contact ring a distance of 560
mm above the top edge of the housing.




Figure 8: Support for descending glass assembly
4 Putting into operation

12
BÜCHI Rotavapor R-187EL
4.6 Installing the descending glass assembly
Use only glassware that is in perfect condition and shows
no signs of cracking, chipping or other damage. Examine
the glassware prior to installation.
•Fasten the distribution piece with PTFE lining ring to
the union nut Use the supplied hook wrench.
•Mount the expansion vessel and tighten the flexible
coupling DN 70 [17] by hand.
•Place the condenser in the support ring and tighten
with the clamp 
•Mount the angular tube using the flexible coupling to
the expansion vessel and the condenser (flexible
couplings DN 70).
•Align the angular tube vertically.
•Tighten all flexible couplings until the springs are depressed
half-way.
•Connect the distillate condenser to the condenser 
using a flexible coupling.
•Preassemble the shut-off valve with adapter and
shut-off valve (flexible couplings DN 25).
•Tighten the outlet valves to the receiving flask using
flexible couplings.
•Place the receiving flask on the support rings 
•Place the pre-assembled shut-off valves –on the
receiving flasks and fasten.
•Raise both support rings until the shut-off valve can
be screwed to the distillate condenser 
•Screw the coolant hose connectors to the condenser.
•Insert the vapour thermometer in the angular socket

•Insert the inlet valve iin the distributor piece 
•Check all flexible couplings and tighten evenly and in
parallel.
•Attach the evaporating flask:
Turn the metal flange until the locking pin meets the
hole. Unscrew the union nut until the evaporating flask
can be inserted. Now screw on the threaded ring by hand
and tighten with the hook wrench. Release the locking
pin.


















4 Putting into operation



Figure 9: Descending glass assembly for the R-187


13
BÜCHI Rotavapor R-187EL
4.7 Installing the reflux glass assembly
Use only glassware that is in perfect condition and shows
no signs of cracking, chipping or other damage. Examine
the glassware prior to installation.
•Screw the condenser support ring  tightly in position at
a height of 770 mm above the top edge of the housing.
•Fasten the adapter with the union nut Use the
supplied hook wrench to tighten in place.
•Mount the reflux distribution piece on the adapter 
and fasten with flexible coupling DN 70.
•Place the condenser in the support ring and connect
to the reflux distribution piece (flexible coupling DN
70).
•Fasten the condenser with clamp 
•Tighten the outlet valves to the receiving flask using
flexible couplings.
•Place the receiving flask on the support rings 
•Preassemble the shut-off valve with adapter and
shut-off valve 
•Place the pre-assembled shut-off valves on the receiving
flask and fasten.
•Connect the distillate condenser to the backflow distri-
butor piece and shut-off valve and fasten with clamp
If necessary, adjust the height with the support ring 
•Tightly screw the coolant hose connectors to the con-
denser.
•Insert the shut-off valve in the backflow distributor piece

•Insert the inlet valve in the adapter 
•Check all flexible couplings and tighten evenly and in
parallel.
•Attach the evaporating flask:
Turn the metal flange until the locking pin meets the
hole. Unscrew the union nut until the evaporating flask
can be inserted. Now screw on the threaded ring by hand
and tighten with the hook wrench. Release the locking
pin.


















4 Putting into operation
Figure 10: Reflux glass assembly for the R-187



14
BÜCHI Rotavapor R-187EL
4.8 Cooling medium
The hydraulic oil circuit is supplied with an cooling coil which
must be used to cool the hydraulic oil. If the Rotavapor is started
up without a cooling system, there is a risk of the hydraulic unit
overheating. The standard version of the Rotavapor R-187 Ex is
designed for coolant temperatures of 5°C and higher. At
temperatures below 5°C the hydraulic oil cools too much,
impairing the hydraulic system´s efficiency. As an option operation
with a cooling brine with a temperaure below 5°C is possible.
Please ask your Büchi Service Centre.
4 Putting into operation
4.9 Connections
Vacuum connection
Hose connector, Ø21 mm external.
Coolant inlet
Hose connector, Ø21 mm external.
(Coolant with temperatures below 5°C can only be used with
a control valve, see Section 4.8.)
Coolant outlet
Hose connector, Ø21 mm external.
Electrical connection
In compliance with the power rating plate (located at back
of housing).

Figure 11: Separate triggering of the oil cooler
Figure 12: Coolant and electrical connections




15
BÜCHI Rotavapor R-187EL
Bath trickle feed
Hose connector, Ø14 mm external
Bath overflow outlet
Hose connector, Ø14 mm external
Control valve for bath trickle feed device
4 Putting into operation


Figure 13: Bath connections
Vacuum hose
Coolant hose, outlet
Coolant hose, inlet
The vacuum connection for the descending glass assembly
is on the distillate cooler



Figure 14: Connections for reflux glass assemby

16
BÜCHI Rotavapor R-187EL
4.10 Wiring
The Rotavapor R-187 is delivered with a fitted power cable
but without a plug.
Check that the voltage of your power supply is the same as that
quoted on the unit´s rating plate.(located on back of housing)
Motor
Motor circuit-breaker
The electrical connection must be installed and checked by an
authorized person.
It is imperative to check the direction of rotation of the hydraulic
motor. See mark on the hydraulic motor hood. If the motor starts
up in the wrong direction, it will be impossible to raise and lower
the bath hydraulically. In this case switch power off immediately
and reverse the phase-wires.
Prolonged use in the wrong direction will damage the hydraulic
motor.
Figure 15: Wiring diagram


4.11 Heating medium
Never operate the heating bath without heating medium!
Suitable heating media are:
•Water (if distilled or demineralised water is used, add some
Borax)
•Heat transfer oil suitable for applications up to 160°C (e.g.
Ucon HTF 14, Fluka AG).
•Water-soluble polyethylene glycol (PEG) (e.g. polyethylene
glycol 600, Fluka AG)
4.12 Installation check
After completing the installation but before carrying out the first
distillation, check the following points:
•Examine the glassware for possible damage.
•Make sure the connections are correctly fastened (vapor,
water, vacuum).
•Check vacuum tightness. (See section 6.6)
4 Putting into operation

17
BÜCHI Rotavapor R-187EL
5 Operating the Rotavapor
Make sure that the instrument was installed correctly as per
the instructions in Chapter 4.
5.1 Position of the controls and indicators
Speed control for rotation of the evaporating flask
Distillate vapor temperature indicator
Pressure gauge
Bath lift lever
Power switch
Control panel of the heating system with display for the
bath-temperature
Switch for heating on/off
Fuse
The bath is lowered automatically when the unit is switched
off or if a power failure occurs. This ensures that the
evaporating flask is removed completelyfrom the heating
source. This only happens, however, when the bath lift lever
is in its central position (neutral).
5 Operating the Rotavapor





Figure 16: Controls and indicators on the R-187 EL, electrical -heated


5.2 Controlling the bath temperature
After switching on the main power of the R-187 you will read
«P.nr»in the upper display of the controller. In the lower the actual
programnumber «X.X». After ca. 5 sec. the controller switches to
the user-mode automatically.
Operation
The operation of the controller is divided into three separate
levels:
•the user-level with all the nominal values which are necessary
for controlling.
•the level which is available after keying in a special code. In
this level the regulation-method with all the parameters is
stored. In this level you can change the regulation method.
The method is programmed in the factory and stored in a
non-volatile memory.
Figure 17: Neutral position of the bath lift lever
Figure 18: Electrical heating controller

18
BÜCHI Rotavapor R-187EL5 Operating the Rotavapor
•the configuration level. This level is available after keying in
another special code. This level is programmed in the factory.
User level
Setpoint temperature:
•Press key «P/3»for 1 sec. The display shows: «USr».
•Press key «P/3»again; the display shows: «SP.1».
•Increase the set point-temperature with the key «(/2», or
decrease the setpoint-temperature with the key «(/4». Confirm
the changed temperature by pressing the key «P/3».
The key «*/1»is for sevice-works by authorized service
technicians only.
Explanation of the symbols
«P.nr»number of the actual program
«USr»user level
«SP.1»setpoint channel 1
«SP.2»setpoint channel 2
«PAr»entrance into the level in which all the parameters are
stored. This level is for servicing the instrument only.
5.3 Points to note when using the Rotavapor
Selecting the distillation temperature
For optimum conditions of distillation, the energy transferred
to the distillation from the bath must also be removed by the
condenser. To guarantee this relationship, it is advisable to
apply the following rule of thumb.
Cooling water ∆T2 Boiling temperature ∆T1 Bath
max. 20 ºC 40 ºC 60 ºC
How do you obtain these conditions?
•Set the bath temperature to 60°C.
•Set the cooling water to a temperature of no higher than
20°C.
•Have the cooling water flow through the condenser at an
approximate rate of 600-700 litres/h.
•Select the working vacuum so that the boiling point of the
solvent becomes 40°C.
•Consult the solvent table on page 21 for the corresponding
vacuum value.
Advantages of a bath temperature of 60°C:
•You can handle the evaporating flask without risk of
scalding.
•Water does not evaporate from the water bath at a high
rate.
•The heating bath energy is utilized with optimum efficiency.
The goal is to have condensation of solvent take place with
in approximately 2/3 to 3/4 of the cooling coils.

19
BÜCHI Rotavapor R-187EL
5.4 Solvent table
5 Operating the Rotavapor
Solvent Formula Molary weight Energy of Boiling point in °C Tightness Vacuum in mbar
in g/mol evaporation in J/g at 1013 mbar in g/cm
3
for boiling at 40 ºC
Acetic acid C
2
H
4
O
2
60.0 695 118 1.049 44
Aceton C
3
H
6
O 58.1 553 56 0.790 556
N-Amylalcohol, n-Pentanol C
5
H
12
O 88.1 595 37 0.814 11
Benzene C
6
H
6
78.1 548 80 0.877 236
n-Butanol, tert. Butanol C
4
H
10
O 74.1 620 118 0.810 25
2-Methyl-2-Propanol C
4
H
10
O 74.1 590 82 0.789 130
Carbontetrachloride, tetra Chloromethane CCI
4
153.8 226 77 1.594 271
Chlorobenzene C
6
H
5
CI 112.6 377 132 1.106 36
Chloroform CHCI
3
119.4 264 62 1.483 474
Cyclohexane C
6
H
12
84.0 389 81 0.779 235
Diethyl ether C
4
H
10
O 74.0 389 35 0.714 850*
1,2,-Dichloroethane C
2
H
4
CI
2
99.0 335 84 1.235 210
1,2,-Dichloroethylene (cis) C
2
H
2
CI
2
97.0 322 60 1.284 479
1,2,-Dichloroethylene (trans) C
2
H
2
CI
2
97.0 314 48 1.257 751
Di isopropyl ether C
6
H
14
O 102.0 318 68 0.724 375
Dioxane C
4
H
8
O
2
88.1 406 101 1.034 107
DMF (Dimethylformamide) C
3
H
7
NO 73.1 153 0.949 11
Ethanol C
2
H
6
O 46.0 879 79 0.789 175
Ethyl acetat C
4
H
8
O
2
88.1 394 77 0.900 240
Heptane C
7
H
16
100.2 373 98 0.684 120
Hexane C
6
H
14
86.2 368 69 0.660 335
Isopropyl alcohol C
3
H
8
O 60.1 699 82 0.786 137
Isoamyl alcohol, 3-Methyl-1-Butanol C
5
H
12
O 88.1 595 129 0.809 14
Methyl ethyl ketone C
4
H
8
O 72.1 473 80 0.805 243
Methanol CH
4
O 32.0 1227 65 0.791 337
Methylenechloride, Dichloromethane CH
2
CI
2
84.9 373 40 1.327 850*
Pentane C
5
H
12
72.1 381 36 0.626 850*
n-Propyl alcohol C
3
H
8
O 60.1 787 97 0.804 67
Pentachlorethane C
2
HCI
5
202.3 201 162 1.680 13
1,1,2,2,-Tetrachloroethane C
2
H
2
CI
4
167.9 247 146 1.595 35
1,1,1,-Trichloroethane C
2
H
3
CI
3
133.4 251 74 1.339 300
Tetrachloroethylene C
2
CI
4
165.8 234 121 1.623 53
THF (Tetrahydrofurane) C
4
H
8
O 72.1 67 0.889 357
Toluene C
7
H
8
92.2 427 111 0.867 77
Trichloroethylene C
2
HCI
3
131.3 264 87 1.464 183
Water H
2
O 18.0 2261 100 1.000 72
Xylene (Isomers mixture) C
8
H
10
106.2 389 25
(o) 144 0.880
(m) 139 0.864
(p) 138 0.861
Table 2: Solvents * only possible when cooling water is 20°C

20
BÜCHI Rotavapor R-187EL5 Operating the Rotavapor
Figure 19: Protecting switch, electrical heating
5.5 Troubleshooting
Malfunction Possible cause Remedy
Flask does not rotate Lock button on gear head not released Turn off motor and release lock button
No hydraulic oil Check oil level or top-out with oil
Hydraulic pump is rotating in wrong direction Call Customer Service
(phases reversed)
Motor circuit breaker has released Remove back cover, press start button,
remount back cover
Evaporating flask rotates Hydraulic hoses reversed Call Customer Service
in wrong direction
Bath does not heat up Polluted thermostat Call Customer Service
Heating element not connected Insert heating plug
Protecting switch is losen Open the socket by loosing, the 4 screws
and activate the protecting switch.
Close the socket again. (Figure 19)
System has a leak Valves open Close valves
Seals defective Check seals
Glass connections leaking Tighten couplings
Table 3: Troubleshooting
Customer Service
The addresses of the official Büchi Customer Service Centres
are listed on the back cover of these instructions. Please contact
your local service centre if any malfunctions arise or if you have
any technical questions or problems with an application.